Telephone system



J. F. TOOMEY. TELEPHONE SYSTEM. APPLICATION FILED APR. 18. I918.

' Patented Dec'.20,1921.

2 SHEETS-SHEET I.

v INVENTOR. JFJbom BY l I l I l LINES. vtikthnhi ATTORNEY APPLICATIONFILED APR. 18, 1918 Patented Dec. 20, 1921.

2 SHEETS-SHEET 2- i n R 5 ILL i i FEM" i I I I i I 'JNVE BY Lt ATTORNEYill illfil) STATES PATENT JOHN F. TOOMEY, OF NEVJ YORK, N. Y., ASSIGNORT0 AMERICAN TELEPHONE AND TELEGRAPH COMPANY, A CORPORATION OF NEW YORK.

TELEPHONE SYSTEM.

Specification of Letters Patent.

T 0 all whom it may concern Be it known that I, JoI-IN F. TOOMEY,residing at New York, in the county of New York and State of New York,have invented certain Improvements in Telephone Systems, of which thefollowing is a specification. I

This invention relates to telephone switchboards and particularly toarrangements associated with a long distance transmission line at acentral office. A

In practice a long distance transmission line may be associated with aplurality of different switchboards and positions at a central office.At one switchboard, positions may be provided for handling .outgoingcalls over the line, and calls coming in over the line may be takencare-of at positions on other switchboards. In addition it may befound-desirable to have the line connected with other boards andpositions suitable for purposes of testing and supervision. If aconnection is made with the line at any one of the positions associatedtherewith, it is desirable to notify the operators at all the otherpositions on the line that the line is busy so that no attempt will bemade to make connections therewith. Accordingly one of the objects ofthis invention consists in the provision at a plurality of the positionsconnected with a long distance transmission line in a central oflice ofmeans for indicating whenever the line is being used.

At periods, such .as at night, when a decrease intraffic might warrant adecrease in the operating force at a central office, it may be founddesirable to have both the incoming and the outgoing calls over the longdistance line handled at positions on a board which would normally beused only for one type of call, such as the'board used for outgoingcalls. In instances when a call is recelved at an incoming board whichrequires the attention of a through operator, such as an operator at anoutgoing board, it is desirable to transfer such a call to an outgoingboard. Accordingly further objects of the invention consists in theprovision of means, which will operate when desired, to inform theoperators at positions .on the outgoing board that there is an incomingcall on the line which it is desired that they should handle. Other andfurther objects of the invention will be clear from the detaileddescription to be given later.

In the arrangements of this invention there is provided at the positionswith which the long distance line is associated, a plurality of dropswhich, when operated, serve as busy signals to show that the lineisbeing used. These drops are all connected to a common conductor sothat, when a source of current is connected thereto, all of the dropswill operate. The ringing current from a call coming in over the longdistance line will operate a relay included in a bridge across the linewhich will operate. relay means under its control to connect a source ofelectrical energv to the common conductor leading to the drops, therebycausing them to operate, and to close a circuit: through the signallamps located at po-' sitions on the incoming board. If it be found insingle instances that an incoming call requires the attention of anoperator at an outgoing board, a plurality of switch ing means areprovided which serve to close the last mentioned circuit through signallamps at positions on the outgoing board instead of at the incomingboard. If operators at positions on either the incoming or outgoingboards make a connection with the transmission line, a circuit will beclosed over the conductors connected to the sleeve contacts of jacks atsuch positions and through one of the'two windings of another relay.This relay serves to deenergize the aforementioned relay means and toextinguish the signal lamps, and substitutes further means forconnecting a source of elec trical energy to the common conductorleading to the drops. If the operator at the test board makes aconnection with the line a circuit will be closed over the conductorleading from the sleeve of the jack at the test board about the windingof another relay. The operation of this relay se ves to energize theabove mentioned relay with the double winding. which functions, asformerly, to extinguish the signal lamps and to understood withreference to the accompany- Patented Dec. 20, 1921.

ing drawing, in the Figs. 1 and 2 of which,

when taken together, is illustrated a circuit diagram of the preferredform of the inven tion. Connected to the long distance transmission lineL at the central office, are shown the switchboards A, B, C and D. BoardA is used for testing purposes, and includes a position at which islocated suitable switch ing means, such as the ack J The board B is usedfor handling incoming calls over the line L and may include a pluralityof positions, each having suitable switching means, such as the jacks Jand The board G is used forha-ndling outgoing calls over the line L andmay include a plurality of positions, each having suitable switchingmeans, such as the jacks J J J and J,. The board 1) is used forpurposesof supervision, and includes a position with switching means, such asthe j acl: J At each of the positions on the boards B, C and D areprovided drops, or busy signals, such as the drops 16, 17, 18, 19, 20,21 and 22. These drops are connected by the conductors 14: and 15 to acommon conductor 12. Bridged across the transmission line L is the relay1,

which responds to ringin current coming in over the line. Under controlof the relay 1 is shown the relay 2, which operates to connect a sourceof electrical energy to the common conductor 12, leading to all theafore mentionedbusy signals or drops. The relay 2 also serves to closethe circuit through the signal lamps27 and 28, located atzpositions onthe incoming board B. For therpurpose of handling incoming calls duringcertain perlods, such as at night, at the outgoing board 0,the'switching means K are pro? vided, which serve to cause circuits tobe closed uponthe operation of relay 2 through the signal lamp 32,located at a position on the outgoing board C, instead of closingcircuits, as formerly, through the signaling means at the incomingboa'rdBL When it is desired in single instances'to switch an incoming call to.the outgoing board C, the switching means. K and K, are provided at theincoming board B. Under the control of these switchingmeans is the relay5, which when operated allows the circuit closed by the operation of therelay 2 to be completed through'the signal lamp 31, located at aposition on the outgoing board C. Connected to the sleeve contacts ofthe jacks at the incoming board by the conductor 34 and connected to thesleeve contacts of the jacks at the outgoing board C by the conductor36,

is a relay 3 with a double winding. When a connection is made with thetransmission line at any of the positions on the boards B or C, therelay? will be operated and con- .nect a source of electrical energy tothe common conductor 12, and accordinglvoperate the beforementioneddrops or busy signals.

Connected to the sleeve contact of the jack at board A is the relay 4:.When a connection is made with the transmission line'L; at the board A,the relay 1 will operate and lose a circuit through the beforementionedrelay3, which will function, as fo1'rner'ly,to connect the source ofelectri al energy to the conductor'leading to the drops or busysigopening the bridge across the transmission line, which includes the,relay 1, and for deenergizing the relay 2, which controls the operationof all the signal lamps. V

The invention may now be more fully understood from the followingdescription of its operation: When a call comes in over the longdistance transmission line L ringing current will be transmitted overthe bridge, including the conductors 6 and the winding'of relay 1, whichbecomes energized. 'The operation of relay 1 closes the followin circuitFrom ground, armature andcontact of relav 1, conductors 7 and 8, windingofrelay2, conductor 9, to battery and ground. .The closing of thiscircuit energizes relay 2, which becomes locked up over the followingcircuit :-From ground and battery, conductor 9, winding of relay2,right-hand contact and armature of relay 2, conductor 10, left-handmiddle contact of relay 3to ground. Operation of relay 2 serves to closethe -following circuit :-'From ground and battery, left-hand middlearmature and contact of relay 2, over conductors 12, 1 1 and 15 to thedrops 16, 17 18, 19, 20, 21, and 22. The closing of this circuitoperates the above-mentioned drops, or busy signals, and informs theoperators at the various positions and switchboards that the longdistance line is in use; The aforementioned operation of relay 2'alsocloses the following circuit :-From ground and battery, conductor 9,left-hand armature and contact of relay 2, over conductors 11, 23 and24:, upper contact of key 7K over conductor '26 to the filaments ofsignal lamps 27 and 28 to ground. This operates the signal lamps 27 and'28, located at the incoming board B, and thereby informs the" operatorsat positions on this board that there is an incoming call on the longdistance line L which it is desired that they should handle.

At periods, such as at night, when a de- 110 crease in traflic mightwarrant a decrease in the operating force at a central oilice, the key Kis thrown. Incomingcalls over the line L will, in thesame manner as hasbeen formerly pointed out, operate the re- 115 lays 1 and 2. Relay 2Will, in the same manner as formerly pointed out, operate the drops orbusy signals;- The circuit formerly closed by the operation of relay 2through the signal lamps 27 and 28, will there is an incoming call onthe line which it 1s desired that she should handle.

When an operator at an incoming board finds that an incoming callrequires the at tention of an operator at an outgoing board, theswitching means K or K located at positions on the board B, may beoperated. The operation of the key K closes the followin circuit :Fromground, contact of key 1 5 conductor 29, winding of relay 5 to: batteryand ground. The closing of this circuit will energize relay 5. Theincoming call over the line L will, in the same manner as has beenformerly pointed out, operate the relays 1 and 2. Due to theenergization of the relay 5, the signaling circuit closed by theoperation of relay 2 will now be as follows :-From gound and battery,conductor 9, left-hand armature and contact of relay 2, conductor 11,right-hand contact and armature of relay 5, over conductor 30, filamentof signal lamp 31 to ground. The closing of this circuit will operatethe signal lamp 31, located ata position on the outgoing board C, andwill notify the operator at such a. position that there is an incomingcall on the line L,, which it is desired that she should handle. Jponthe closing of this last-mentioned circuit, the relay 5 will becomelocked up over its right-handing winding. A similar operation will takeplace should the key K, be thrown, and the de scription thereof will beomitted.

If a connection is made with the trans mission line L at positions onthe board B by the switching means J 2 or J,, a potential from a sourcein the link circuit will be ap plied over the following circuitz-Slleevecontact of jack J conductors ll and 34,.

left-hand windin of relay 3, over conductor 35, left-hand middlecontacts of relay 5 to ground. This will energize the relay 3. The

energization of relay 3, by pulling up its right-hand armature, connectsa source of energy to the conductor 13, leading to the common conductor12, which leads to the drops or busy signals. By this means the busysignals will remain in operation after the relay 2 has ceased tooperate, and until the connection with the transmission line at theboard B is terminated. The operation of the relay 3, by pulling up itsleft-hand armatures, opens the locking circuit ton. merly closed throughthe winding of relay 2, and opens the bridge across the transmissionline, including the conductors 6 and the winding of relay 1.. If aconnection is made with the long distance line L, at any or" theposition on the outgoing board C by the switching means such as J J J.or J,, a potential from a source in the link circuit will be appliedover the following circuit From the sleeve contact of one of saidswitching means, over conductors 36 and 42, right-hand winding of relay3 to ground.

By the closing of this circuit the relay 3 will become operated and willperform the same functions as previously described.

It a connection is made with the long distance line L, at the board A,by the jack 3,, a potential from a source in the link circuit will beapplied over the following circuit:--Sleeve contact of jack J overconductor 37, winding of relay 4, conductor 38, resistance 39 to ground.The closing of this circuit will operate the relay 4. The operation ofrelay a closes the following circuit From ground and battery, resistance43, cont-act and armature of relay 4, over conductor 4-2, right-handwinding of relay 3 toground. The closing of this last-mentioned circuitenergizes the relay 3, which will accordingly function in the same mannor as previously pointed out to operate the drops, to hold open thebridge including the relay 1 and to hold open the locking circuit aboutthe relay 2. The operation of relay 4 also serves to apply a busypotential to the conductor terminating at the sleeve contacts of thejacks at the board C so that they will test busy.

While the invention has been disclosed as embodied in certain specificarrangements which have been deemed desirable, it will be understoodthat it may be capable of embodiment in many other arrangements withoutdeparting from the spirit of the invention as defined in the appendedclaims.

What is claimed is:

1. In a telephone exchange system, a trunk transmission line terminatingat a central oiiice in a plurality of sets of switching terminalslocated at different switchboard positions, indicating means located ata plurality of said switching terminals, signaling means located at oneof said last mentioned sets 01 switching terminals, and means responsiveto current coming in over said transmission line for operating saidindicating means and said signaling means.

2. in a telephone exchange system, a trunk transmission line terminatingat a central other: in a plurality of sets of switching terminalslocated at different switchboard positions, indicating means located ata plurality of said switching terminals, sig naling means located at oneof said last mentioned sets of switching terminals, a relay included ina bridge across said transmission line and responsive to current comingin over said transmission line, and means controlled by said relay foroperat ing said indicating means and said signaling means.

3. In a telephone exchange system, a transmission line terminating at acentral ofiice in a plurality of sets of switching terminals, a linerelay connected with the transmission line, indicating means actuatedupon i116 energization of said line relay, link circuits for extendingthe transmission line, a relay associated with a plurality of said setsof switching terminals and operating upon connection of one of the linkcircuits therewith to disconnect said line relay from the transmissionline and to continue the operation of said indicating means, and a relayassociated with another of said sets ofswitching terminals andresponsive to the connection of a link circuit therewith to cause theoperationoof the relay associated with said other sets-of switchingterminals.

4:. In a telephone exchange system, a

' transmission line terminating at a central oflice ina plurality ofsets of switching ter 'minals, indicating means located at a pluralityof said switching terminals, link circuits for extending thetransmission line,- a

trolled by said second mentioned relay for altering the electricalpotential of terminals at another ofsaid sets ofswitching terminals.

In testimony whereof, I have signed my name to this specificationthis5th day of April, 1918. v

' 7 JOHN F. TOOMEY.

